It says, "[Up] [Down] [Up] [Right] will shut it down." We found it blowing in the wind in the Carnea District.
Using the command "[Up] [Down] [Up] [Right]", Ein shut down two enemy Golems.
Golem Manual

Golem Manual is an Event Item in Riviera: The Promised Land that can be used to avoid two Golem encounters in the Tetyth stage.

Acquirement: In the final room of Tetyth's Carnea District, upon defeating the Elder Wyrm, attempting to advance will trigger a minigame event. Complete it successfully to obtain the manual.

Function: Allows for the Golem encounters in Stage 4 to be avoided via manual input, but only if the code is memorized by viewing the item's description in the Inventory. The input command is only effective during this stage.